Set up and send custom alerts to custom notification channels

Firebase offers default Crashlytics alerts (see the alerting overview page). However, these default alerts and their notification channels may not be sufficient for your needs.

In these cases, you can use Cloud Monitoring to send custom alerts to custom notification channels based on Crashlytics data (and optionally Firebase sessions data) that you've exported to Cloud Logging.

To use Cloud Monitoring for custom alerts, you set up an alerting policy, which describes the circumstances under which you want to be alerted and how you want to be notified.

For example, if your crash-free rate goes below a specific threshold, Cloud Monitoring can send a customized alert message to a specific email address or post it to a third-party service, like Discord, Slack, or Jira. You can also fully customize the information sent in the alert, like including helpful deep-links into the Firebase console or company-specific troubleshooting information.

In the Google Cloud documentation, learn more about Cloud Monitoring and alerts, including pricing.

Prerequisites

1. Make sure your Firebase project is on the pay-as-you-go Blaze pricing plan.

2. Set up export to Cloud Logging of Crashlytics data and (optionally) Firebase sessions data.

3. Set up notification channels.

Set up an alerting policy

The following are high-level instructions; for detailed instructions, see the Google Cloud documentation (for example: Create metric-threshold alerting policies or Use PromQL to create alerting policies).

As part of running queries, you can set up either a log-based alert or a SQL-based alert:

• Set up a log-based alert:

  1. Run a query in Logs Explorer.

  2. Click the Add alert button that appears.

  3. Follow the on-screen instructions to add a log-based alert.

• Set up a SQL-based alert:

  1. Run a query in Logs Analytics.

  2. Click the Add alert button that appears.

  3. Follow the on-screen instructions to add a SQL-based alert.

Alternatively, you can set up alerts for your log-based metrics by using the policy configuration tool in the Google Cloud console, where you can choose one of the following options:

• Builder: The console UI provides a guided workflow to build the alerting policy.

• PromQL: You provide a PromQL query for your alerting policy

  Example PromQL query

  For example, say that you've created two log-based metrics for your exported Crashlytics and Firebase sessions data:

  • One metric named firebase/crashlytics_events with a label of errorType, and it's defined as:

    logName="projects/PROJECT_ID/logs/firebasecrashlytics.googleapis.com%2Fevents"

  • Another metric named firebase/session_events with a label of eventType, and it's defined as:

    logName="projects/PROJECT_ID/logs/firebasecrashlytics.googleapis.com%2Fsession_events"

  Here's an example PromQL query using these log-based metrics to alert when your crash-free drops below 70%:

  1 - (sum by (project_id) (rate({__name__="logging.googleapis.com/user/firebase/crashlytics_events", errorType="FATAL"}[5m])) /
  sum by (project_id) (rate({__name__="logging.googleapis.com/user/firebase/session_events", eventType="SESSION_START"}[5m]))
  ) < 0.7